Sue. They haven't been convicted yet so you missed the "alleged" before your accusation. Why is that important? It's possibly that when the Online Safety Act comes into effect next year that sites such as this forum may decide to close as they don't have the resources to moderate its content if people are careless about what they say. Some sites are already announcing their plans to close (the isn't the best article about this but unlike the Telegraph's and New Scientist's it's not behind paywall):
https://m.slashdot.org/story/436559